<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./one.js"></script>
</head>
<body>
    

    <script>
        var obj={
            birth:1990,
            getAge:function (){
                var b=this.birth;
                var fn=() =>new Date().getFullYear() - this.birth;
                console.log(this.birth);
                return fn();
            }
        }
        const a= obj.getAge();
        
        console.log(a);
        
        
        
    </script>
</body>
</html>